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arXiv · 2609.14037

Beam Squint and Aperture--Bandwidth Limitations in Wideband RIS-Assisted THz Links

Waqas Khalid·Chiew Foong Kwong·David Chieng·Qianyu Liu
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Abstract

This paper analyzes the ergodic rate of a wideband reconfigurable intelligent surface (RIS)-assisted terahertz link under beam squint and finite-resolution phase control. Independent Rayleigh fading on the two RIS-assisted hops produces double-Rayleigh cascaded amplitudes. Exact second- and fourth-order channel moments are derived by incorporating the frequency-dependent array response and phase-quantization errors. Moment matching then provides a Gamma approximation for the received power on each subcarrier and a tractable closed-form approximation for the wideband ergodic rate. A first-null bandwidth approximation characterizes the aperture--bandwidth limitation of frequency-flat RIS control. Monte Carlo simulations validate the analytical framework.

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Waqas Khalid, Chiew Foong Kwong, David Chieng, Qianyu Liu. 2026-09-12. Beam Squint and Aperture--Bandwidth Limitations in Wideband RIS-Assisted THz Links. https://arxiv.org/abs/2609.14037

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